Method of controlling combustion in internal-combustion engines



0. APPEL METHOD CONTROLLING COMBUSTION IN INTERNAL-COMBUSTION ENGINESOriginal Filed July 22, 1945 Nov. 28, 1950 m l l J INVENTOR 95mm 4/ 5;

ATTO R N EY Patented Nov. 28, 1950 METHOD OF CONTROLLING COMBUSTION ININTERNAL-COMBUSTION ENGINES Oscar Appel, Paterson, N. J.

Continuation of application Serial No. 495,722, July 22, 1943. Thisapplication August 7, 1946,

Serial No.688,981

2' Claims.

Internal-combustion engines using liquid fuel may be regarded asexisting in two general types -the type in which the total quantum ofthe fuel, by a carburetor or by spraying, is first mixed with the totalquantum of the air, as before or during compression, the mixture is thencompressed to a state in which the temperature of the mixture is lessthan the compression-ignition temperature thereof, and finally locallyeffective and supplementary heat (afforded by a spark) is applied to themixture; and the type (commonly known as the Diesel or compression--ignition engine) in which the air alone (or it may be a mixture of theair and a part of the fuel) is first-compressed to the state in whichthe indicated fluid content is high enough in temperature to initiatecombustion when more of the fuel is then added thereto, and then thelatter fuel is, as by spraying, delivered progressively to said content.In each case what is'contemplated is that the combustion shall beprogressive as distinguished from occurring as detonation (or thesimultaneous combustion of the whole or a substantial part of thewholecontent of said space)-in the first type because, the compression of thealready complete or ultimate mixture being short of thecompression-ignition temperature, the indicated supplementary heatexpedient acts more or less locally to initiate the combustion whichcontinues or progresses due to the heat of such combustion plus the heatof a compression; and in the second type because the spraying is itselfprogressive and so] progressively goes to complete the ultimate mixture,with consequent progressive combustion thereof.

The present invention relates to engines of the first indicated type, orwhat I herein term the "igniter-dependent type, thus to distinguish fromthe Diesel engine wherein ignition depends on compression to bringthefuel-air'mixture at least approximately m ne temperature forignition, and it consistsin. an-improved method of effecting combustionin such igniter-dependent engines whereby to avoid more'completely thanhas heretofore been possible the mentioned detonation in any partpf thefuel-air mixture not yet consumed by normal combustion instituted by atimed ignition. According thereto, given what I shall hereinafter termthe operating space" of the engine, the total quantum of the airconstituent of the ultimate mixture is incorporated in said space andthe fluid content of such space is compressed to the same state thatsaid ultimate mixture would be compressed short of the ignition-pointthereof in order to effect combustion only by resort to supplementaryheat; during the period of such incorporating and compressin only a partof the total quantum of the fuel constituent of said ultimate mixture isintroduced into said space; and, while the resulting preliminary mixtureremains at the temperature at which combustion thereof will be initiatedonly by resort to supplementary heat, to a limited part of the fuel-aircontent present in said space extraneously derived heat at willcienttemperature to initiate combustion thereof is suddenly applied and theremaining part of the fuel is sprayed into said space.

In Patent No. 2,012,086, to one Mock (incidentally, not for what I havetermed an igniterdependent type but a Diesel type engine) air isadmitted-to the cylinder space and therefrom passes to acombustion-chamber-adjunct of such space and thence to a so-calledflame-chamber containing a glow-plug as an igniter, the combustionchamber being formed to maintain the air whirling therein in the form ofa torus and the flame chamber being adapted to maintain in calm state abody of fluid, and, after some fuel has been sprayed into the isolatedbody of air in the flame chamber, and the heat of compression has raisedthe temperature of the mixture adjacent the igniter to its ignitionpoint and (with due regard for a phenomenon-known as ignition-delayinherent in engines fully or partially dependent upon'compression forignition) ignition is established thus to form a localized calm flamingpreliminary mixture in the flame chamber, a second charge of fuel issprayed through this calm flaming mixture into the whirling air-torus inthe combustion chamber. My method distinguishes from the method thuscharacterized in that, being applied to an igniterdependenttype engine,the spraying is not directed through an isolated portion of the enginespace containing a constantly active igniting medium and in which a calmflame is present. but to a space containing a preliminary mixture andhaving no provision for isolating flame and which space I therefore termthe operating space" of the engine. Such operating space" may be theusual space coactive with the piston in effecting intake andcompression. Further, the ignition is effected suddenly in the form ofextraneously derived heat, as a spark.

In the appended claims the order of suddenly applying extraneous heatand the spraying is not essential. I may suddenly apply the extraneouslyderived heat at the indicated temperature during or after the sprayingof the remaining part of the fuel; or I may suddenly apply theextraneously derived heat at said temperature to the preliminary mixtureand effect the spraying during the combustion that is initiated by suchapplication-of the heat. A distinct feature of novelty of my inventionis that the heat is extraneously derivedand suddenly applied to alimited part of the fuel-air content, thus distinguishing from knownmethods in which the heat is not extraneously derived nor is it suddenlyapplied but exists stored in the walls of the cylinder or someadjunctive space thereof such as a retort, being the heat of previouscombustion.

In reference to the second of the two indicated ways it is noted asfollows: It is known that when ignition of a fuel-air mixture iseffected and combustion proceeds from the igniter, a portion of themixture (usually remote from the igniter) becomes compressed, as anincident of more or less of the first part of the combustion process, tothe compression-ignition point, with consequent detonation of suchportion. An advantage of my method in such a case is that the dischargeof said'remaining part of the fuel has the effect of cooling thepreliminary mixture so that detonation, of such an isolated limitedportion of the mixture is prevented; and I preferably direct the saidremaining part of the fuel constituent to such limited portion, theincoming fuel acting quite advantageously to cool said portion and thusprevent compression-ignition of said limited portion.

To illustrate possible conditions which may exist in the practice of mymethod, but without being limited thereby, I show the same in theaccompanying drawing diagrammatically and in the case of a four-strokeengine during an intake and a compression stroke,

' Figs. 1 and 2 respectively showing the first and I second of the twoways above set forth; and

Figs. 3 and 4 showing, during an intake and a compression stroke, theorder in which injection and ignition occur according to what is shownby Figs. 1 and 2, respectively.

In Figs. 1 and 2, l is the cylinder and 2 the piston of theengine, thelatter being connected with the engine crank 3 by the pitman or link 4.

In both figures the art of the fuel which goes to form the aforesaidpreliminary mixture is assumed to have been introduced to the operatingspace s of the engine during the intake stroke orin the period from a tob in Fig. 3 or Fig. 4 and the piston is in the position at which suchmixture has been compressed to the same state that it would becompressed, if the whole quantum of each of the air and fuelconstituents were present, in order to undergo combustion only by resortto supplementary heat. Top dead center is indicated in Figs. 3 and 4 bythe character at. Said operating space is as hereinbefore defined.

In Fig. 1, 5 is the means, as an injector in the form of a spray nozzle,for progressively discharging the aforesaid remaining part. of the fueland 6 is the means (here assumed to be a spark-plug) by which theextraneously derived supplementary heat is here applied. The period ofinjection (or progressive discharge of said remaining part of the fuel)is indicated in Fig. 3 by the are c and the period within which thesupplementary heat is assumed to become effective is indicated by thearc d, the inception of the latter period being during the injectionperiod. The relative positions of the means 5 and 6 as here shown are ofcourse not particularly material in this case.

In Fig. 2, 8 is the spray nozzle and 1 a sparkplug, they being sopositioned that the spray is discharged to the preliminary mixture atthat portion thereof, as at the left of the dotted arcuate line e, whichtends to be compresesd to the compression-ignition point by combustionof the remaining portion of said mixture previously initiated by thespark plug. The period of injection in this case is indicated in Fig. 4by the are c' and the period in which the spark may become active isindicated by the arc d, such period beginning prior to period c.

It will be understood that in either case the one injector, as a spraynozzle, may be used to discharge both the fuel constituent of thepreliminary mixture and the remaining part of the fuel and there may beprogressive discharge of fuel for the forming of the preliminary mixtureeither with or to the air of such mixture.

Of course, also it is of advantage tohave the fuel of the preliminarymixture vaporized as completely as possible at the time the remainingpart of the fuel constituent is discharged into the operating space.Hence, I prefer to form the preliminary mixture during the intake periodof the engine, thevaporizing being an incident of presence of heat orreduction of pressure.

Engines of the second type first herein referred to have approximatecompression-range limits in the ratios of 12 and 25 to 1. Generallyspeaking, engines of the first of these types using fuel which possessesno special detonation-inhibiting expedients have approximatecompression-range limits in the ratios of 6 and 2 to 1. In the case ofthe latter type of engines if the mixture is compressed more than sixtimes, in the absence of special detonation-inhibiting expedientsdetonation inevitably occurs.

According to my invention an engine into whose operating space the fuelis sprayed and in the operation of which heat supplementingthe heat ofcompression is resorted to may be operated at a substantially highercompressionrange limit than 6. This is of course because detonation ofthe preliminary mixture, being too lean to undergo combustion as anincident of temperature-rise due only to compression, is avoided on suchcompression, and such detonation is avoided subsequently because themixture following ignition is made to assume its ultimate richnessprogressively, even where the combustion is initiated in the preliminarymixture.

This application is a continuation of my application Ser. No. 495,722,filed July '22, 1943, now abandoned. A

Having thus fully described my invention what engine having a cylinder,piston and combustion chamber, which comprises compressing a combustiblemixture of fuel and air in said combustion chamber, spark igniting saidcombustible mixture to form a flame front advancing to trap and highlyheat end gases of combustible composition in a zone of said combustionchamber, said flame front tending to raise the temperature and pressureof said end gases sufiiciently to cause spontaneous ignition andresultant detonation, and after ignition and said advancement of theflame front through a substantial portion of the combustion chamber onany cycle but prior to the spontaneous ignition of said end gases insaid zone on the same cycle, injecting fuel into said zone to change thecomposition oi'.said end gases and prevent spontaneous ignition andresultant detonation.

2. A method of operating an igniter-dependent internal combustionengine, the operation of which is subject to limitation due todetonation, said engine having a cylinder, piston and combustionchamber, which comprises compressing a combustible mixture of fuel andair in said combustion chamber, locally igniting said com- 10 6 of saidend gases in said zone on the same cycle, injecting fuel into said zoneto change the composition of said end gases and prevent spontaneousignition and resultant detonation.

OSCAR APPEL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 673,160 Diesel Apr. 30, 1901959,951 LOrange May 31, 1910 1,096,405 Thomson May 12, 1914 1,239,523Rogers Sept. 11, 1917 1,392,556 Cottard Oct. 4, 1921 1,616,157 WernerFeb. 1, 1927 2,012,086 Mock Aug. 20, 1935 2,368,423 Olsen Jan. 30, 1945

